Dominica is the Latin word for Sunday. For centuries, the Catholic Church—as well as Protestant Churches which had liturgical calendars—referred to the cycle of Scripture lessons for Sundays as the “Dominical Cycle.” While the term no longer appears in any Missal or Book of Common Prayer, these cycles still exist: in the Roman Missal of the ordinary form, there are three dominical cycles of lessons for Ordinary Time and one for privileged seasons; in the extraordinary form there is only one dominical cycle of lessons throughout the year, regardless of the season. I have chosen to resurrect this ancient term because “lessons from the secondary dominica” is so much more aesthetic than “readings for Sunday B of Ordinary Time,” which sounds more like a choice of combination dinners on a Chinese menu.
The term “feria” refers to any day not a Sunday to which no feast of any class is attached. While the Roman Missal of the ordinary form no longer uses the term, both the Missal and Office of the extraordinary form do, as do the Liturgicons of the Churches of the Byzantine Rite. In the ordinary form, there are two cycles of lessons for ferial days in Ordinary Time, and one for privileged seasons; the Missal of the extraordinary form also identifies ferial days, but does not assign Scripture lessons to them, as the readings on ferial days are usually repeated from the preceding Sunday, unless the feria is that of a privileged season.
When indicating on this site from where the readings are taken on a given day, I have rejected the confusing terminology employed by the Roman Missal Third Edition, which employs such terms as “Proper of Time,” “Proper of Saints” and “Common of Saints.” Instead, I use the term “proper” only when a particular day has readings of its own, even if those readings are not required, which is what the word “proper” means. Even the Missal itself makes this mistake whenever it says "The Gospel for this day is proper"; what it really means to say is "The Gospel for this day is required." "Proper" only means that it pertains to that particular day, required or not. If a day is a memorial of a saint with no proper readings (or for which the proper readings are optional), and the celebrant is given the option to use the regular weekday readings or those from the common for that class of saint, you will know which I'm using by noting whether the readings are "from the proper", "from the common” or "from the feria.”
Thus, on this site, the Scripture lessons for any given day come from one of only four places: the dominica, the feria, the common or the proper, all depending on the rubrics or the options allowed for that particular day. In all cases, the actual Scripture citations are given in full as well. And, for those still a bit confused, what I call...

"the primary dominica" = Sunday cycle A, "the secondary dominica" = Sunday cycle B, "the tertiary dominica" = Sunday cycle C, "the primary feria" = weekday cycle I, "the secondary feria" = weekday cycle II, "the feria" = weekday readings during privileged seasons with only one cycle, "the proper" = readings provided for a specific day, whether required or merely recommended, and "the common" = optional readings selected from the Common of Saints when these are allowed and nothing specific is required.

...and with four, you get eggroll.

What's with all the Psalms?

Some have inquired why I include a psalm when listing the lessons in the extraordinary form, especially since there is no "Responsorial Psalm" in that form; however, in actuality, there is: what the Missals of St. Pius V and St. John XXIII call the "Gradual" is what became the "Responsorial Psalm" in the Missal of Bl. Paul VI, though it usually consists of only one or two verses and is not sung in a responsorial way. On certain Sundays and feasts which have a penitential character, as well as on Ember Days, an additional Psalm is added, called the "Tract," which is why there are two psalms indicated for those days (during Lent, the Tract corresponds to the Gospel Acclamation of the ordinary form, replacing the Alleluia).
The Psalm at Mass, regardless of whether it's called Gradual, Tract or Responsorial Psalm, is a legitimate Scriptural lesson of the Mass, and should not be excluded if one chooses to meditate on the readings of the day. I have been known, on occasion, to preach exclusively on the Psalm of the day, a practice I picked up from reading the Parochial and Plain Sermons of Bl. John Henry Newman. Just keep in mind that the Roman Missal of the ordinary form numbers the Psalms according to the Hebrew Psalter, as do most modern Bibles today; the Missals of the extraordinary form use the numbering system of the Greek Psalter, as do the Liturgicons of the Byzantine Churches; thus, when listing the psalms, I respect the numbering system used in that particular Missal or Liturgicon.

What do you mean by "or"?

In the ordinary form, when designating the celebrations of saints on this site, I have employed a device of my own invention: when the day is what the Missal calls an “obligatory memorial,” I designate the day by the title of that memorial: such as, “The Memorial of Saint Dominic, Priest.” When the Missal indicates that a day is an “optional memorial,” I designate it by both its ferial title and its sanctoral title, using the conjunction “or”: such as, “The First Wednesday of Advent; or, the Memorial of Saint Francis Xavier, Priest.” I do this because the use of banal terms like “optional” or “obligatory” are simply not worthy of a liturgical calendar … in my opinion.

Hey, aren't you off by a week?

The Third Edition of the Roman Missal in English makes use of a banal and verbose terminology in referring to ferial days, such as “Friday of the Third Week of Ordinary Time”; on this site I have employed a more grammatically pleasing economy of words much gentler to the eye and ear, such as “The Third Friday of Ordinary Time,” which I contend is far superior.
This, however, presents somewhat of a problem in the season of Lent which begins, not on a Sunday, but on a Wednesday; thus, the day known as Ash Wednesday is the actual First Wednesday of Lent, making the Wednesday of the following week “The Second Wednesday of Lent,” even though it occurs in what the Missal has called “The First Week of Lent.” Even so, I still contend that the designation, “Wednesday of the First Week of Lent,” with its double preposition, is cumbersome and grammatically inferior, not to mention the fact that it's inaccurate, since a week's worth of Lent will have already passed.
Therefore, I have decided to continue the convention already in use on this site, which means that, in the week following the First Sunday of Lent (that is, the first full week of Lent), Tuesday will be called “The First Tuesday of Lent,” and the following day will be called “The Second Wednesday of Lent,” confident that the intelligent reader will know what this means; and, this will carry on in the successive weeks. In other words, what is called “Thursday of the Second Week of Lent” in the Roman Missal, will be called “The Third Thursday of Lent” on this site.
As an aside, it is interesting to note that the Thursday, Friday and Saturday following Ash Wednesday, while clearly days of Lent, have a unique character all their own which distinguishes them from the rest of the season, in much the same way that the days from December 17th until Christmas Eve are distinguished from the rest of Advent. Both the ordinary and extraordinary forms of the Roman Missal designate these days as days “after Ash Wednesday” rather than days of the First Week of Lent, but it is clear that this is more than just a pedestrian way to avoid confusion regarding the first half-week of Lent and the first full week: in the Breviarium Romanum of the extraordinary form, from Ash Wednesday through the following Saturday, the Variable Ordinary used is the one labeled “Throughout the Year”; the Variable Ordinary labeled “The Season of Lent” is not engaged until the First Sunday of Lent.

How am I supposed to know on what "rite" the homily is based?

On those days where I choose to list the day's designations and Scripture citations for more than one Tradition (ordinary form, extraordinary form, and Ruthenian recension), you will know on which the homily is based by which one is listed first on the left side of the page; though, in a very few cases, a homily may be applied to more than one.
Regarding the different ranks of liturgical celebrations, a summary of how the various Rites designate them may be helpful, as they do not use the same terms in the same way. In all three calendars featured on this site the various classes of liturgical days correspond to each other as indicated in the following chart, according to the terminology used in the respective missals/liturgicons themselves:

The Ordinary Formof the Roman Rite.

The Extraordinary Formof the Roman Rite.

The Ruthenian Recensionof the Byzantine Rite.

Solemnity.

Feast of the First Class.

Solemn Holy Day.

Feast.

Feast of the Second Class.

Simple Holy Day.

Memorial.

Feast of the Third Class.

Feast.

[Outside a privileged season:]Optional Memorial.

Commemoration.

[No corresponding day.]

[In a privileged season:]Commemoration.

[In a privileged season:]Seasonal Weekday.

[Ash Wednesday & Holy Week:]Feria of the First Class.

Feria.

[Dec. 17th to 23rd, Ember Days& Vigils of 1st Class Feasts:]Feria of the Second Class.

[Advent, Lent & Passiontide:]Feria of the Third Class.

[Outside a privileged season:]Ordinary Weekday.

[Outside a privileged season:]Feria of the Fourth Class.

The days known as “Optional Memorials” in the ordinary form and “Commemorations” in the extraordinary form are concomitant with one another and, in both cases, when occurring outside any privileged season, it is entirely up to the priest whether to observe them. At the same time, however, they are both observed and not observed in slightly different ways.
In the ordinary form, when choosing to observe an optional memorial, the lessons from the feria are usually retained so as not to interrupt the continuity of the Scriptural narrative, with the lessons provided in the proper (if there are any) being optional along with any selection of lessons from the appropriate common, unless the Missal indicates that a proper lesson must be used if the memorial is observed. Optional memorials are usually provided only with a Collect. Rarely do they have antiphons and other orations proper to them, so the priest is free to choose any from the appropriate common or use the ones from the feria; but, even if these other elements are provided in the proper, the ones from the feria may still be used. Nevertheless, the color of the saint is worn. In point of fact, most of what is said here is true of memorials which are not optional, other than the fact the it's up the priest whether to observe them. When choosing not to observe an optional memorial, nothing at all from the saint is taken; everything at Mass comes from the feria, and the color of the season is worn.
In the extraordinary form, if the priest chooses to offer the Mass for the commemoration, the lessons from the proper (if there are any) or from the specific common indicated must be taken; this makes sense given that ferias outside privileged seasons have no texts of their own, with the lessons, antiphons and orations from the previous Sunday being repeated, so there is no Scriptrual narrative to interrupt. The antiphons and orations from the proper (if there are any) or from the specific common indicated must also be taken, and the color of the saint is worn. In other words, if the priest chooses to observe a commemoration, he does so in the same manner as if it were a Third Class Feast, the only diffence being that it's up to him whether to observe it. When choosing not to observe a commemoration, the Mass from the feria is offered in toto, including the lessons, antiphons and orations from Sunday; however, the Collect, Secret and Postcommunion from the proper (if there are any) or from the indicated common are still added to those of the previous Sunday (so there are two of each), but the color of the season is worn.
In privileged seasons, optional memorials in the ordinary form (and even memorials during Lent) automatically become what that Missal then calls “commemorations,” and these are observed in a similar way in both forms: in the ordinary form, only the Collect is taken, with everything else taken from the seasonal feria; in the extraordinary form, an additional Collect, Secret and Postcommunion are added to those of the seasonal feria, from which comes everything else. In both cases, the lessons from the feria are always taken, and the color for the season is always worn. In both forms, there is no option to offer a Mass for a commemoration during a privileged season.
In the Byzantine Tradition, there is no concept of a privileged season, and the days of saints are celebrated in the same way throughout the year, regardless of the season, with no option to observe or not to observe them. This is why the days on the Roman calendars known as "optional memorials" and "commemorations" have no corresponding day on the Byzantine calendar.
Note that what is commonly referred to as a “Holy Day of Obligation” in the Latin Church—or a “Day of Precept” in the Byzantine Churches—does not appear on the above chart; this is because it does not constitute a rank of feast in and of itself, but simply means that an obligation has been attached to a day of the highest rank in that particular Church. In the Byzantine Tradition, whether a particular Solemn Holy Day is designated a Day of Precept varies from jurisdiction to jurisdiction.
Also notice that the chart above does not incorporate Sundays. In both forms of the Roman Rite, a Solemnity or a Feast of the First Class may or may not take precedence over a Sunday, depending on the nature of the celebration, e.g., whether it is a feast of the Lord, or of Our Lady, or of a saint, or during a privileged season. In the Byzantine-Ruthenian Rite, however, whenever a feast of high rank falls on a Sunday—or two such feasts fall on the same day—the two celebrations are combined, with double readings and double texts; in fact, even if more than two such days fall on the same date, they are all combined into the same service, rather than one taking precedence over another, a feature unique to the Eastern Churches. This explains why Byzantine services are sometimes quite lengthy, as there could conceivably be three or more Epistles, three or more Gospels, and three or more sets of chants in between them, all related to the various celebrations coinciding on that day. In some cases, this may even be true of colliding celebrations of different ranks; for example, the day of the Holy Prophet Elijah has become so popular with the Ruthenian faithful that, even though it is just a simple feast, if it were to fall on a Sunday or collide with a Solemn Holy Day, it would still be observed, and it's lessons and chants would be added.

What's a "triodion"? What's a "menaion"? What's a ... Oh, I give up.

In the Byzantine-Ruthenian Rite, the triodion is the cycle of lessons and texts for the pre-lenten and lenten seasons; the pentecostarion is the cycle for Pascha (Easter), Pentecost, the post-Pentecost season (ordinary time), as well as Philips Fast (Advent) and Christmas; and the menaion is the cycle for feasts and the days of saints.
Prior to the First Sunday of Advent, 2017, the Scripture citations for the Ruthenian recension of the Byzantine Tradition were given for each post. This tradition was singled out on this site because it was in a Church of that recension that I served for eighteen years, and is the recension of the Byzantine Tradition with which I am familiar. Though I no longer retain faculties in an eparchy (diocese) of that recension, homilies based on that Church's liturgical celebrations may be found in the archives, as this site was started while I was serving as a pastor in that Church; and, the chart above showing how the various ranks of days compare with one another will remain unchanged. Other recensions (forms) of the Byzantine Rite used by Churches in union with Rome, such as Ukrainian, Russian, Melkite, etc., would not differ extensively, though they may have individual feasts particular to their respective Churches.

Why include all these different rites and forms anyway?

Because the Catholic Church is more than just the Roman Rite, and the Roman Rite is more than just the Novus Ordo. St. John Paul II said that the Church must learn to breath with both lungs; I contend that, even with only one lung, one needs to breath more deeply to use all the chambers of that lung.
Traditionalists and liberals alike in the Latin Church, who like to lament the existence of two "forms" of the Roman Rite, should take note that this is nothing new in the Church; their unease with the concept stems from the limited experience of having the Rite by which they worship used by only one Church for so many centuries. In the Christian East, there was never a Rite of worship used by only one Church, and each Church using that particular Rite has always had its own "form," usually called a "recension." By far, the most widely used Rite in Christianity is the Byzantine or Constantinopolitan Rite, and there are seven separate and distinct Churches in union with Rome which make use of that Rite, each one publishing it's own Liturgicon (Missal) containing rubrics, options and feasts—sometimes even liturgical colors—that pertain only to that particular recension. With this perspective, it's clear that the decision of the Latin Church to offer her faithful a plurality of forms with which to celebrate the one Roman Rite was long overdue.

Are you for real?

One might legitimately ask whether all this is just a bit anal-retentive. The answer, of course, is “yes”; but, if there is any value at all in pursuing a recovery of the sacred in Catholic worship, one should start at the beginning, and the beginning of anything is the definition of one's terms, followed by an attention to detail. As Saint Thérèse of the Child Jesus is reported to have said at the time she served as sacristan for the Carmel of Lisieux, “I would rather die than violate the most insignificant rubric.” Considering that the liturgy of the Church presents to us—that is, makes present to us—our Divine Savior, I cannot find her attributed attitude extreme.